Medical instrument

ABSTRACT

A medical instrument includes a swingable operating section formed of a pair of forceps which rock around a first rocking axis, a tubular sheath having a distal end portion situated on the proximal end side of the operating section, the distal end portion having a circular-section portion having a circular cross section perpendicular to the longitudinal central axis thereof and a pair of flat portions formed by cutting the opposite sides of the circular-section portion and in sliding contact with the respective proximal end portions of the forceps, a manipulator which advances and retreats in a longitudinal direction of the sheath, thereby rocking the forceps around the first rocking axis, and a junction which connects the manipulator for rocking motion around a second rocking axis with respect to the forceps in the flat portions, the junction being situated on or near a reference plane passing through the longitudinal central axis of the sheath and extending parallel to the second rocking axis when the operating section is closed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a Continuation Application of PCT Application No.PCT/JP02/09828, filed Sep. 25, 2002, which was not published under PCTArticle 21(2) in English.

This application is based upon and claims the benefit of priority fromthe prior Japanese Patent Application No. 2001-292358, filed Sep. 25,2001, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a medical instrument.

2. Description of the Related Art

A prior art example of a medical instrument (see Patent Publication No.2000-279418) for continuously endoscopically picking an organic tissuewill now be described with reference to FIGS. 17A to 17D and 18A to 18E.

As shown in FIG. 17A, this conventional medical instrument 201 comprisesan insert section 202 that can be inserted into an endoscope and aninstrument control section 203 that is fixed to a proximal end portionof the insert section 202. The insert section 202 is composed of asheath 204 and a tissue picking portion 205 that is fixed to a distalend of the sheath 204.

As shown in FIG. 18A, an inner tube 208 for use as a lumen for excisedslice recovery is passed through the bore of the sheath 204. Further,forceps control wires 209 a and 209 b for operating a pair of forceps212 a and 212 b (see FIGS. 17B and 17C), along with the inner tube 208,are passed through the bore of the sheath 204. The respective proximalends of the control wires 209 a and 209 b are fixed integrally to aforceps control slider 234 (see FIG. 17A).

As is evident from FIGS. 17B and 17C, the forceps 212 a and 212 b havemovable jaws 220 a and 220 b on their respective distal end portions.The movable jaws 220 a and 220 b grasp and excise a part of the organictissue. Further, the forceps 212 a and 212 b have rocking arms 221 a and221 b for rocking the movable jaws 220 a and 220 b on their respectiveproximal end portions. The approximate central portions of the forceps212 a and 212 b are mounted on supporting pins 222 a and 222 b (see FIG.18B), respectively. The forceps supporting pins 222 a and 222 b areattached to a tip cover 211, extend through flat portions 215 a and 215b, respectively, of the tip cover 211, and can rock independently ofeach other.

The respective proximal ends of the rocking arms 221 a and 221 b arerockably fitted with forceps control wire holding pins 223 a and 223 bfor use as rocking pins that hold the forceps control wires 209 a and209 b, individually. These forceps control wire holding pins 223 a and223 b penetrate through holes 229 a and 229 b formed in the rocking arms221 a and 221 b, respectively.

As is also shown in FIGS. 18A to 18C, a suction nozzle 213 is formedintegrally on the distal end of the inner tube 208. The suction nozzle213 has an oval cross section that is perpendicular to the longitudinaldirection of the insert section 202. Further, the distal end portion ofthe suction nozzle 213 that has a suction port 219 on its distal endprojects into a tissue receiving space 227 of the movable jaws 220 a and220 b through an opening portion 216 of the tip cover 211.

As shown in FIG. 17A, the instrument control section 203 has a suctionport 238 connected to the proximal end of the inner tube 208 and aliquid conveying port 240 connected to the proximal end of a residualspace 228. The suction port 238 is to be connected to anegative-pressure generator 235 by means of a tissue recovery container237 and a suction tube 236. Further, a syringe 239 for use as fluidsupply means can be connected to the liquid conveying port 240.

As shown in FIG. 17D, the tissue recovery container 237 is composed of acontainer housing that has six vials 246 a to 246 f and six vial inletholes 249 a to 249 f provided corresponding to the six vials 246 a to246 f, individually. The vials 246 a to 246 f serve as independenttissue traps that are independent of one another. In this case, thevials 246 a to 246 f are removably attached to their corresponding vialinlet holes 249 a to 249 f without failing to maintain airtightness.

The following is a description of treatment for the organic tissue bymeans of the medical instrument 201 constructed in this manner.

First, the interior of the body cavity is observed through the endoscopeas the endoscope and the medical instrument 201 are moved in the bodycavity, and the tissue picking portion 205 is guided to a position whereit faces a subject tissue of a mucous membrane. Subsequently, theforceps control slider 234 is moved to the distal end side to push outthe pair of forceps control wires 209 a and 209 b to the distal endside. Thereupon, the forceps control wire holding pins 223 a and 223 brotate as they move together with the rocking arms 221 a and 221 b tothe distal end side. Accordingly, the forceps 212 a and 212 b rockaround the forceps supporting pins 222 a and 222 b, respectively,whereupon the movable jaws 220 a and 220 b swing open around the centralaxis of the tissue picking portion 205 (see FIGS. 17B and 17C).

When the movable jaws 220 a and 220 b are open, as shown in FIG. 19,thereafter, edge portions 225 a and 225 b of the movable jaws 220 a and220 b are caused to engage a subject tissue 262. In this state, theforceps control slider 234 is moved to the proximal end side, so thatthe pair of forceps control wires 209 a and 209 b are pulled back to theproximal end side. Thereupon, the movable jaws 220 a and 220 b areclosed to excise the subject tissue 262, and a tissue slice 263 is heldin the tissue receiving space 227 of the jaws 220 a and 220 b (see FIG.20).

When the tissue slice 263 is held and recovered in the tissue receivingspace 227 of the jaws 220 a and 220 b in this manner, thenegative-pressure generator 235 is actuated to evacuate air from theinner tube 208 and thus the suction nozzle 213, thereby forming anegative pressure therein. If a fluid is then fed into the residualspace 228 in the sheath 204 by means of the syringe 239, the fluid isjetted out into the tissue receiving space 227 of the jaws through theopening portion 216 of the tip cover 211, and runs the tissue slice 263into the suction nozzle 213. The tissue slice 263 that has been run inthe suction nozzle 213, along with the supplied fluid, is sucked intothe inner tube 208 under the negative pressure produced by means of thenegative-pressure generator 235, and is carried into a suction line 255of the tissue recovery container 237 through the suction port 238without jamming. The tissue slice 263 that is carried into the suctionline 255 is captured by a mesh filter 252 a of the vial 246 a. Further,the fluid that is sucked in together with the tissue slice 263 a to thesuction line 255 passes through the mesh filter 252 a and a vial throughhole 251 a, and is sucked into the negative-pressure generator 235.

In the conventional medical instrument 201 constructed in this manner,the forceps control wires 209 a and 209 b are fixed by spreading, laserwelding, etc. after they are passed through forceps control wire holdinggrooves 224 a and 224 b formed in the forceps control wire holding pins223 a and 223 b. Since the forceps control wire holding pins 223 a and223 b are spaced individually outward from the central axis plane of theforceps (or the plane of contact between the edge portions 225 a and 225b of the movable jaws) (that is, the forceps control wire holding pins223 a and 223 b are located at a good distance from a plane that passesthrough the longitudinal central axis of the tissue picking portion 205(tip cover 211) and extends parallel to the longitudinal central axis ofthe forceps control wire holding pins 223 a and 223 b), outward endfaces 223 f of the forceps control wire holding pins 223 a and 223 b areobliquely formed to match a circumferential surface C of the forceps(see FIG. 18C). This is done because the outer diameter of the medicalinstrument must be made smaller than the inner diameter of a forcepschannel of the endoscope, since the instrument is inserted in theforceps channel when it is used. In fixing the forceps control wires 209a and 209 b to the forceps control wire holding grooves 224 a and 224 bin the forceps control wire holding pins 223 a and 223 b by spreading orlaser welding, however, a satisfactory connection space (working space)for the forceps control wires 209 a and 209 b cannot be secured with useof the inclined working plane. Thus, positioning and fixing operationsare harder than when a substantially horizontal plane is used.Naturally, in order to give priority to workability, the respectiveoutward end faces 223 f of the forceps control wire holding pins 223 aand 223 b may possibly be formed to be substantially horizontal surfacesin the state of FIG. 18C where the forceps control wire holding pins 223a and 223 b are spaced outward from the central axis plane of theforceps. In this case, however, the corner portions of the substantiallyhorizontal surfaces project from the circumferential surface, so thatthe maximum outer diameter increases. Thus, the resistance of insertioninto the endoscope is so high that the operating efficiency lowers.

In the conventional medical instrument 201 constructed in this manner,moreover, the forceps supporting pins 222 a and 222 b are attached tothe tip cover 211 and extend through the flat portions 215 a and 215 b,respectively, of the tip cover 211. Therefore, head portions 300 of theforceps supporting pins 222 a and 222 b are bound to project into thebore of the tip cover 211, so that the size of the suction nozzle 213that is passed through the bore is restricted inevitably.

In the conventional medical instrument 201 constructed in this manner,furthermore, a part 264 of the tissue slice 263, excised and recovered,is inevitably nipped between the edge portions 225 a and 225 b of themovable jaws 220 a and 220 b when the subject tissue 262 is grasped andexcised by means of the movable jaws 220 a and 220 b (see FIG. 20). Thisis because cutting edges on the edge portions 225 a and 225 b of themovable jaws 220 a and 220 b cannot completely excise the tissue. Morespecifically, the tissue picking portion 205 is separated from thesubject tissue 262 without releasing the tissue, whereby the tissue isfinally torn away. When the part 264 of the tissue slice 263 is thusnipped between the edge portions 225 a and 225 b of the movable jaws 220a and 220 b, it is hard to move the tissue slice 263 into the suctionport 219 if a negative pressure is applied to the suction port 219 toreflux the fluid to the suction port 219 through the opening portion 216of the tip cover 211.

Naturally, in this case, the nipped tissue 264 can be released if theforceps control slider 234 is moved to the distal end side to open themovable jaws 220 a and 220 b. If the movable jaws 220 a and 220 b arefully opened, however, the tissue slice 263 inevitably adheres to themovable jaw 220 a or 220 b and leaves the suction port 219. Inconsequence, it is hard to suck in and recover the tissue. If the fluidis jetted out through the opening portion 216 of tip cover 211 in thisstate, the tissue slice 263 may possibly fall off the tissue pickingportion 205 under the jet pressure of the fluid.

In order to move the tissue slice 263 successfully to the suction port219 while releasing the nipped tissue 264, therefore, the movable jaws220 a and 220 b should be opened slightly or by half at the most.However, the operator requires skill and subtle manipulation to operatethe forceps control slider 234, thereby moderately opening the movablejaws 220 a and 220 b. Thus, the treatment inevitably takes extra time.

BRIEF SUMMARY OF THE INVENTION

The object of the present invention is to provide a medical instrumentthat enjoys high operating efficiency and assembling performance.

The above object is achieved by the following medical instrument. Themedical instrument comprises: an openable/closable operating sectionformed of a pair of forceps which rock around a first rocking axis; atubular sheath having a distal end portion situated on a proximal endside of the operating section, the distal end portion having acircular-section portion having a circular cross section perpendicularto a longitudinal central axis thereof and a pair of flat portionsformed by cutting the opposite sides of the circular-section portion andin sliding contact with respective proximal end portions of the forceps;manipulators which advance and retreat in a longitudinal direction ofthe sheath, thereby rocking the forceps around the first rocking axis;and junctions which connect the manipulators for rocking motion around asecond rocking axis with respect to the forceps in the flat portions,the junctions being situated on or near a reference plane passingthrough the longitudinal central axis of the sheath and extendingparallel to the second rocking axis when the operating section isclosed.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 is a perspective view of a medical instrument according to afirst embodiment of the present invention;

FIG. 2A is an enlarged perspective view of the distal end portion of themedical instrument of FIG. 1;

FIG. 2B is an enlarged side view of the distal end portion of themedical instrument of FIG. 1;

FIG. 3A is a lateral sectional view of the distal end portion of themedical instrument of FIG. 1;

FIG. 3B is a longitudinal sectional view of the distal end portion ofthe medical instrument of FIG. 1;

FIG. 4A is a sectional view taken along line 4A-4A of FIG. 3B;

FIG. 4B is a sectional view taken along line 4B-4B of FIG. 3B;

FIG. 4C is a sectional view taken along line 4C-4C of FIG. 3B;

FIG. 4D is a sectional view taken along line 4D-4D of FIG. 3B;

FIG. 5 is a perspective view of an instrument control section of themedical instrument of FIG. 1;

FIG. 6 is a perspective view of the instrument control section of themedical instrument of FIG. 1;

FIG. 7A is a perspective view of a ring valve body;

FIG. 7B is a side sectional view of the ring valve body of FIG. 7A;

FIG. 7C is a sectional view taken along line E-E of FIG. 7B;

FIG. 7D is a sectional view corresponding to FIG. 7C, in which adirection of suction is switched;

FIG. 8A is a perspective view of a tissue recovery trap;

FIG. 8B is a perspective view showing the way the tissue recovery trapin the state of FIG. 8A is pushed in;

FIG. 9 is a perspective view of a trap body;

FIG. 10A is a sectional view showing the trap body in engagement with atissue trap mounting portion;

FIG. 10B is a sectional view showing the trap body not in engagementwith a tissue trap mounting portion;

FIG. 11A is a perspective view showing the way one trap is severed fromthe trap body;

FIG. 11B is a perspective view of the severed trap;

FIG. 11C is a perspective view showing the severed trap in a samplebottle;

FIG. 12 is a view showing the medical instrument of FIG. 1 having itsforceps open and held against a tissue;

FIG. 13 is a view showing a state in which the forceps in the state ofFIG. 12 are closed to recover and hold a tissue slice therein;

FIG. 14 is a view showing a state in which the forceps in the state ofFIG. 13 are released from an operating force and opened for a givenangle;

FIG. 15A is a lateral sectional view of the distal end portion of amedical instrument according to a second embodiment of the presentinvention;

FIG. 15B is a longitudinal sectional view of the distal end portion ofthe medical instrument according to the second embodiment of the presentinvention;

FIG. 16A is a sectional view taken along line 16A-16A of FIG. 15B;

FIG. 16B is a sectional view taken along line 16B-16B of FIG. 15B;

FIG. 16C is a sectional view taken along line 16C-16C of FIG. 15B;

FIG. 16D is a sectional view taken along line 16D-16D of FIG. 15B;

FIG. 17A is a schematic view of a conventional medical instrument;

FIG. 17B is a perspective view of the distal end portion of the medicalinstrument of FIG. 17A;

FIG. 17C is a side view of the distal end portion of the medicalinstrument of FIG. 17A;

FIG. 17D is a perspective view of a tissue recovery container;

FIG. 18A is a sectional view of the distal end portion of the medicalinstrument of FIG. 17A;

FIG. 18B is a sectional view taken along line 18B-18B of FIG. 18A;

FIG. 18C is a sectional view taken along line 18C-18C of FIG. 18A;

FIG. 18D is a sectional view taken along line 18D-18D of FIG. 18A;

FIG. 18E is a sectional view taken along line 18E-18E of FIG. 18A;

FIG. 19 is a view showing the medical instrument of FIG. 17 having itsforceps open and held against a tissue; and

FIG. 20 is a view showing the way the forceps in the state of FIG. 19are closed to recover and hold a tissue slice therein.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention will now be described withreference to the drawings.

FIGS. 1 to 14 show a first embodiment of the present invention. As shownin FIG. 1, a medical instrument 1 of the present embodiment comprises aninsert section 2 and an instrument control section 3. The insert section2 can be inserted into a forceps channel of an endoscope (not shown),and can be inserted together with the endoscope into the body cavity.The instrument control section 3 is fixed integrally to a proximal endof the insert section 2. The insert section 2 is composed of a sheath 4and a tissue picking portion 5 that is fixed integrally to a distal endof the sheath 4.

As shown in FIG. 3B, the sheath 4 is composed of a sheath inner wall 6and a sheath skin 7 that protects the outer surface of the sheath innerwall 6. For example, the sheath inner wall 6 used is a closely-woundcoil (not shown) formed of a stainless steel wire that is rolled into arectangular cross section. Thus, the stiffness of the closely-wound coilitself and the sheath 4 can be enhanced, and a wide bore can be securedin the sheath 4.

The sheath skin 7 is formed by coating the outer surface of the sheathinner wall 6 with a chemical substance, such as tetrafluoroethylene,low-density polyethylene, or high-density polyethylene. Since thesechemical substances ensure a smooth outer surface after coating, thesheath 4 can be easily inserted into the forceps channel of theendoscope. Since these chemical substances are highly airtight andwatertight, moreover, the airtightness and watertightness of the sheath4 can be maintained.

Thus, the sheath 4 has a dual structure including the sheath inner wall6 and the sheath skin 7. Accordingly, the sheath 4 can enjoy durabilityto resist movement that is involved in organic tissue picking operationby means of the medical instrument 1 and the endoscope. Further, thesheath 4 can enjoy flexibility such that it can smoothly bend to matchthe internal shape of the body cavity. Furthermore, the airtightness andwatertightness of the bore of the sheath 4 can be maintained.

As shown in FIG. 3A, an inner tube 8 is passed through the bore of thesheath 4. The inner tube 8 is formed as a lumen for recovery excisedslice that transfers an implant (excised slice) 63 a (see FIG. 13),which is excised from an organic tissue (internal tissue) 62 (see FIG.12) mentioned later, from the distal end of the sheath 4 to the proximalend. Further, the inner tube 8 has its distal end airtightly connectedto a suction nozzle 13 (mentioned later) of the tissue picking portion 5and its proximal end airtightly connected to a tissue trap mountingportion 37 (mentioned later) of the instrument control section 3.

In the present embodiment, the cross section of the inner tube 8 in adirection perpendicular to its longitudinal direction is set to 1.0 mm²or more. If the inner tube 8 is sized in this size, the tissue oncesucked in through the suction nozzle 13 can be transported to theinstrument control section 3 without clogging the inner tube 8. Further,the inner tube 8 is formed of a flexible material that can maintain theairtightness of the region from the suction nozzle 13 to the tissue trapmounting portion 37. The material may be a chemical substance formingsmooth inner and outer surfaces, such as tetrafluoroethylene,low-density polyethylene, or high-density polyethylene, or asuperelastic metallic material.

A pair of forceps control wires (manipulators: independent actuatormeans) 9 a and 9 b are passed through the bore of the sheath 4,extending throughout its length in the longitudinal direction. Theseforceps control wires 9 a and 9 b range with the inner tube 8 as theyare passed through the sheath 4. As they are advanced or retreated, apair of forceps 12 a and 12 b (mentioned later) can be operatedindependently. The forceps control wires 9 a and 9 b have their distalends connected to the forceps 12 a and 12 b, respectively, and theirproximal ends fixed integrally to a forceps control slider (independentactuator means, mentioned later) 34 (see FIG. 1) of the instrumentcontrol section 3. The forceps control wires 9 a and 9 b are made of amaterial that cannot easily snap or buckle and is not susceptible tobending, e.g., stainless spring steel wires or monofilament formed of asuperelastic wire material.

As shown in FIG. 3A, forceps control wire skins 10 a and 10 b cover thesurfaces of the forceps control wires 9 a and 9 b, respectively. Theseforceps control wire skins 10 a and 10 b are formed of a chemicalsubstance, such as tetrafluoroethylene, low-density polyethylene, orhigh-density polyethylene, which can form a finished smooth surface.With use of these forceps control wire skins 10 a and 10 b, the slidingresistance of the forceps control wires 9 a and 9 b against the innersurface of the sheath inner wall 6 can be lowered.

As shown in FIGS. 2A to 4D, the tissue picking portion 5 is composed ofa tip cover 11 for use as a distal end portion, an operating section 90,and the suction nozzle 13 (mentioned later). The tip cover 11 is fixedintegrally to the distal end of the sheath 4. The operating section 90is formed of a pair of forceps 12 a and 12 b that are rockably supportedon the tip cover 11. The suction nozzle 13 is fixed integrally to thedistal end of the inner tube 8. The tip cover 11 has a cylinder portion(circular profile portion) 14 on its proximal end side and a pair offlat portions (formed by cutting the opposite sides of the cylinderportion, for example) 15 a and 15 b on its distal end side. In thiscase, the flat portions 15 a and 15 b are arranged symmetrically withrespect to a central axis O of the tissue picking portion 5 in adirection perpendicular to the rocking direction of the forceps 12 a and12 b. Further, the tip cover 11 is provided with an opening portion 16at its distal end. The opening portion 16 has an oval cross section thatis perpendicular to the central axis O of the tissue picking portion 5(see FIG. 4C).

Further, the tip cover 11 has forceps control wire outlet portions(abutting portions) 18 a and 18 b in its transit portions 17 a and 17 bbetween the cylinder portion 14 and the flat portions 15 a and 15 b. Theforceps control wires 9 a and 9 b are led out of the bore of the sheath4 through the forceps control wire outlet portions 18 a and 18 b.

The forceps 12 a and 12 b have a pair of movable jaws 20 a and 20 b,respectively, on their distal end side. These movable jaws 20 a and 20 bgrasp a part of the organic tissue 62 (see FIG. 12), excise it as atissue slice 63 a (see FIG. 13), and holds the tissue slice 63 a.Further, the forceps 12 a and 12 b have rocking arms 21 a and 21 b forrocking the movable jaws 20 a and 20 b around a first rocking axis O1,respectively, on their proximal end side. The rocking arms 21 a and 21 bare in sliding contact with the flat portions 15 a and 15 b,respectively.

Forceps supporting pins 22 a and 22 b having the first rocking axis O1are formed integrally on the flat portions 15 a and 15 b, respectively,of the tip cover 11. The respective approximate central portions of theforceps 12 a and 12 b are mounted on the supporting pins 22 a and 22 b,respectively. The respective distal ends of the forceps supporting pins22 a and 22 b are mechanically spread to form pin flat portions 2221 aand 2221 b. Thus, the forceps 12 a and 12 b are rockably supported onthe flat portions 15 a and 15 b, respectively, of the tip cover 11. Morespecifically, the forceps supporting pins 22 a and 22 b that define thefirst rocking axis O1 are composed of shank portions 2222 a and 2222 band spread portions 2221 a and 2221 b (see FIG. 4B). The shank portions2222 a and 2222 b protrude radially outward from the flat portions 15 aand 15 b, respectively. The spread portions 2221 a and 2221 b are formedon the respective distal ends of their corresponding shank portions 2222a and 2222 b, and are larger in outer diameter larger than the shankportions 2222 a and 2222 b.

Forceps control wire holding pins (junctions) 23 a and 23 b, which serveas rocking pins for individually holding the forceps control wires 9 aand 9 b, are mounted on the respective proximal ends of theircorresponding rocking arms 21 a and 21 b. The pins 23 a and 23 b arerockable around a second rocking axis O2. In this case, the forcepscontrol wire holding pins 23 a and 23 b penetrate through holes 29 a and29 b formed in the rocking arms 21 a and 21 b, respectively.

One end sides of the forceps control wire holding pins 23 a and 23 bthat face the flat portions 15 a and 15 b, respectively, of the tipcover 11 have diameter larger than that of the other end sides. Formedon the other end sides of the forceps control wire holding pins 23 a and23 b are forceps control wire holding grooves 24 a and 24 b, whichengage and hold the forceps control wires 9 a, respectively. After therespective distal end portions of the forceps control wires 9 a and 9 bare passed through the forceps control wire holding grooves 24 a and 24b, respectively, the forceps control wires 9 a and 9 b and the forcepscontrol wire holding grooves 24 a and 24 b are subjected to spreading,laser welding, etc. By doing this, the forceps control wires 9 a and 9 band the forceps control wire holding pins 23 a and 23 b are fixedintegrally to one another.

When the forceps 12 a and 12 b are closed, in the present embodiment,moreover, the forceps control wire holding pins 23 a and 23 b aresituated overlapping the central axis O (that is, the forceps controlwire holding pins 23 a and 23 b are situated on or near a referenceplane P that passes through the longitudinal central axis O of thesheath 4 and extends parallel to the second rocking axis O2) (see FIGS.3B and 4C). Therefore, one end face (outward end face) 98 of each offorceps control wire holding pins 23 a and 23 b that face (or areopposed to) the flat portions 15 a and 15 b of the tip cover 11 aresubstantially in the form of a flat surface (see FIG. 4C). As theforceps control wire holding pins 23 a and 23 b are situated overlappingthe central axis O of the tissue picking portion 5, moreover, theforceps supporting pins 22 a and 22 b and the forceps control wireoutlet portions 18 a and 18 b are situated in positions eccentric to thecentral axis O of the tissue picking portion 5 (that is, a plane thatpasses through the first rocking axis O1 and extends parallel to thereference plane P is not coincident with a plane that passes through thesecond rocking axis O2 and extends parallel to the reference plane P,and the first rocking axis O1 is not on the reference plane P).

A plurality of bent portions 64 a and 64 b are formed on the respectivedistal end portions of the forceps control wires 9 a and 9 b so as toextend along the forceps control wire holding pins 23 a and 23 b fromthe forceps control wire outlet portions 18 a and 18 b. These bentportions 64 a and 64 b are formed in a manner such that they never touchor interfere with the forceps control wire outlet portions 18 a and 18 bwhen the respective distal ends of the movable jaws 20 a and 20 b areopen at an angle wider than about 10° and narrower than 45° (see FIG.14). When the movable jaws 20 a and 20 b are fully closed, moreover, thebent portions 64 a and 64 b touch and interfere with the forceps controlwire outlet portions 18 a and 18 b, whereby they are elasticallydeformed (see FIG. 13).

At least one of the respective edge portions 25 a and 25 b of themovable jaws 20 a and 20 b is formed sharp-edged by cutting orpolishing. Further, recesses 26 a and 26 b are formed inside the movablejaws 20 a and 20 b, respectively. These paired recesses 26 a and 26 bcooperate to define a tissue receiving space 27 that holds the tissueslice 63 a and prevents it from slipping out. Thus, the respective edgeportions 25 a and 25 b of the movable jaws 20 a and 20 b are designed toengage each other without a gap.

Preferably, the forceps 12 a and 12 b are formed of stainless steelmaterial, or a rigid resin, such as ABS resin, or polycarbonate, whichhas high strength and ensures satisfactory sharpness for an edge tool.Further, the tip cover 11 and the forceps 12 a and 12 b, which havecomplicated shapes and require high precision, should be formed byinjection-molding a resin or metal or by forging. Thus, mass productioncan be achieved at low cost.

As mentioned before, the suction nozzle 13 is integrally fixed to thedistal end of the inner tube 8. As is evident from FIGS. 2 and 3, thedistal end portion of the suction nozzle 13 that has a perfectlycircular suction port 19 at its distal end projects into the tissuereceiving space 27 of the movable jaws 20 a and 20 b through the openingportion 16 of the tip cover 11. Further, the tissue receiving space 27has a circular cross section that is perpendicular to the longitudinaldirection of the insert section 2. The outer diameter of the suctionport 19 is set so that it can be covered by the circular cross section.A proximal end side portion 85 of the suction nozzle 13 that is situatedin the bore of the tip cover 11 has an oval cross section that isperpendicular to the longitudinal direction of the insert section 2.Although it is situated in the bore of the tip cover 11, the proximalend side portion 85 securely enjoys a cross section wide enough to allowthe passage of the tissue slice 63 a. Further, a taper portion 86 isformed on a transit portion of the suction nozzle 13 that connects thesuction port 19 and the proximal end side portion 85. The taper portion86 smoothly joints the suction port 19, which has the circular crosssection, and the inner surface of the proximal end side portion 85.

A residual space 28 for use as a liquid conveying lumen is definedbetween the tip cover 11 and the suction nozzle 13. The distal end ofthe residual space 28 communicates with the tissue receiving space 27 ofthe movable jaws 20 a and 20 b, while its proximal end is connected to areflux port 40 (mentioned later) of the instrument control section 3through the bore of the sheath 4. In the present embodiment, the crosssection of the residual space 28 that is perpendicular to itslongitudinal direction is adjusted to 0.5 mm² or more.

As shown in FIGS. 1, 5 and 6, the instrument control section 3 has acontrol section body 31, a supporting rod 32, and a ring-shaped forcepscontrol slider (actuator means) 34. The control section body 31 isairtightly connected to the proximal end of the insert section 2. Thesupporting rod 32 is integrally fixed to the proximal end of the controlsection body 31 in its longitudinal direction. The forceps controlslider 34 is fitted on the supporting rod 32 and is slidable in thelongitudinal direction of the supporting rod 32. In this case, thesupporting rod 32 penetrates a center hole of the forceps control slider34 in its axial direction, and a suction control slider 42 is slidablymounted on its proximal end. Accordingly, the forceps control slider 34can slide in the longitudinal direction of the supporting rod 32 betweenthe control section body 31 and the suction control slider 42. Thesuction control slider 42 can also slide in the longitudinal directionof the supporting rod 32 on the proximal end side of the forceps controlslider 34. The suction control slider 42 is provided with a liquidconveying port 40 that can directly connect a syringe 39 (see FIG. 1)and the like, which will be mentioned later. Further, the inside of theliquid conveying port 40 is lure-tapered to have a smooth surface thatfacilitates insertion of fluid supply means such as the syringe 39.Besides the syringe 39, a motor-driven liquid conveying pump (not shown)or the like can be used as a fluid source that is connected to theliquid conveying port 40.

The forceps control slider 34 is connected with the respective proximalend portions of the paired forceps control wires 9 a and 9 b that extendthrough the interior of the supporting rod 32. If the forceps controlslider 34 is moved along the supporting rod 32 toward the distal end (ortoward the control section body 31), therefore, the forceps 12 a and 12b open in the manner mentioned later. If the forceps control slider 34is moved along the supporting rod 32 toward the proximal end (or towardthe suction control slider 42), on the other hand, the forceps 12 a and12 b close in the manner mentioned later.

Further, a suction line 55 is provided in the supporting rod 32 so as toextend covering its overall length. The distal end of the suction line55 opens in the tissue trap mounting portion 37 (mentioned later). Theproximal end of the suction line 55 is connected to a suction port 38that is set on the proximal end of the supporting rod 32. Furthermore, aliquid conveying line 41 is passed through the interior of thesupporting rod 32. The distal end side of the liquid conveying line 41passes through the interior of the control section body 31 and isairtightly connected to the proximal end of the sheath 4. Morespecifically, the distal end portion of the liquid conveying line 41 isairtightly connected to the residual space 28 in the sheath 4 in thecontrol section body 31. The proximal end side of the liquid conveyingline 41 is airtightly connected to the liquid conveying port 40.

The instrument control section 3 has a tissue trap mounting portion 37in which the proximal end of the inner tube 8 opens. In the controlsection body 31, the inner tube 8 is airtightly connected to afront-side opening seal 43 of the tissue trap mounting portion 37, andcommunicates with an opening 43 a of the front-side opening seal 43. Theproximal end side of the front-side opening seal 43 is provided with arear-side opening seal 44 that faces the front-side opening seal 43 at agiven distance therefrom. The front-side opening seal 43 and therear-side opening seal 44 define between them a through hole 46 for trapinsertion in which a trap body 70 of a tissue recovery trap 69(mentioned later) can be inserted.

Further, the proximal end side of the rear-side opening seal 44 isprovided with a tissue recognition window 45 that is formed of atransparent material. With use of this tissue recognition window 45, anoperator can visually recognize the state of the trap body 70 of thetissue recovery trap 69 to be inserted into the through hole 46 for trapinsertion through the rear-side opening seal 44. The distal end of thesuction line 55 opens on the lateral side of the internal space of thetissue recognition window 45 in an airtight state, and communicates withan opening 44 a of the rear-side opening seal 44.

As shown in FIG. 7A, a ring valve body 47 is removably fixed to thesuction port 38 provided on the proximal end of the supporting rod 32.The distal end of the ring valve body 47 is provided with a lure male 48that is fitted in the suction port 38 and a rock ring 49 that isrockable coaxially with the lure male 48. An internal thread is formedon the inner surface of the rock ring 49. The internal thread is screwedwith a projection 50 on the outer surface of the suction port 38.Further, the inner surface of the suction port 38 is formed with a slowlure-tape. The lure male 48 is inserted into the suction port 38 so thatthe outer surface of the lure male 48 is fitted on the lure-taperedsurface of the inner surface of the suction port 38. If the internalthread on the inner surface of the rock ring 49 is caused to engage theprojection 50 on the outer surface of the suction port 38 in this state,therefore, the ring valve body 47 can be firmly coupled to thesupporting rod 32. A grip ring 33 is provided integrally on the proximalend of the ring valve body 47.

A sliding tubular line 53 is provided in the ring valve body 47. Thesliding tubular line 53 forms a sliding path for a valve seat 57 thatcontrols communication between various passages in the ring valve body47. As a push rod 52 that is coupled to it advances or retreats, thevalve seat 57 moves airtightly in contact with the inner surface of thesliding tubular line 53 (or moves in the direction of insertion of thelure male 48 into the suction port 38), and airtightly separates spacesin front and at the back of the sliding tubular line 53.

Further, a release tubular line 54 that communicates with the slidingtubular line 53 at its proximal end is provided in the ring valve body47. The release tubular line 54 has its inner diameter smaller than thatof the sliding tubular line 53 (and therefore, smaller than the outerdiameter of the valve seat 57), and is composed of a first pipe portion54 a and a second pipe portion 54 b. The first pipe portion 54 a extendsin the axial direction of the sliding tubular line 53 from the proximalend of the sliding tubular line 53. The second pipe portion 54 b extendsat right angles to the first pipe portion 54 a. The second pipe portion54 b communicates with the outside by means of a return port 56.

An internal communication passage 58 that communicates with the slidingtubular line 53 is provided in the ring valve body 47, and situated onthe distal end side more than the release tubular line 54. One end ofthe internal communication passage 58 opens in a sidewall region of thesliding tubular line 53 at a given distance from the release tubularline 54. The other end of the internal communication passage 58communicates with the lure male 48 and opens to the outside.

Inside the ring valve body 47, moreover, an external communicationpassage 59 is located between the release tubular line 54 and theinternal communication passage 58. The external communication passage 59extends parallel to the second pipe portion of the release tubular line54 and communicates with the outside by means of an external port 51.

The push rod 52 that slides the valve seat 57 in the sliding tubularline 53 is composed of a small-diameter portion 52 a on the proximal endside coupled to the valve seat 57 and a large-diameter portion 52 b onthe distal end side. The large-diameter portion 52 b projects from thesliding tubular line 53 without failing to keep the sliding tubular line53 airtight inside. The large-diameter portion 52 b is coupled to thedistal end portion of the ring valve body 47 by means of an elasticvalve spring 60. More specifically, the distal end portion of the valvespring 60 is fixed to the large-diameter portion 52 b of the push rod52, while the proximal end portion of the valve spring 60 is fixed tothe distal end portion of the ring valve body 47. Further, the valvespring 60 always urges the push rod 52 to project from the slidingtubular line 53. The valve spring 60 is formed of a chemical substance,such as silicone rubber, various elastomers, etc. It is contracted byelastic deformation when pushed in and is restored to its original shapewhen released from the push force.

According to the present embodiment, moreover, the respective lengths ofthe push rod 52 and the valve spring 60 are set so that the valve seat57 is situated between the internal communication passage 58 and theexternal communication passage 59 when the valve spring 60 has itsnatural length (or is in a fully stretched state) so that the valve seat57 closes the release tubular line 54 when the valve spring 60 iscontracted. Thus, the valve spring 60 has its natural length longer thanthe distance between the release tubular line 54 and the externalcommunication passage 59.

The external port 51 is connected to a negative-pressure generator 35(see FIG. 1) by means of a suction tube 36. Further, the return port 56is connected to a suction input connector (not shown) of the endoscopeby means of a return tube 61. A motor-driven vacuum pump, manual vacuumpump, rubber ball, or large-sized syringe may be used for thenegative-pressure generator 35 as suction means that is connected to theexternal port 51.

FIGS. 8A to 11C show details of the tissue recovery trap 69 that isattached to the tissue trap mounting portion 37. As shown in FIG. 8A,the tissue recovery trap 69 is composed of the elongate trap body 70 anda support 71. The trap body 70 can be airtightly inserted into thethrough hole 46 for trap insertion that is formed in the tissue trapmounting portion 37. The support 71 engages the tissue trap mountingportion 37 and the trap body 70.

As shown in FIG. 9, the trap body 70 is provided with a plurality ofdepressions 72 a to 72 e that are arranged in its longitudinaldirection. The depressions 72 a to 72 e are arranged at given spaces ina line in the longitudinal direction of the trap body 70, and their baseportions are partially penetrated to the opposite side. Further, thebase portions of the depressions 72 a to 72 e are provided with meshfilters 73 a to 73 e, respectively, which have a large number of fineorifices.

The depressions 72 a to 72 e have enough size and depth enough toreceive and hold the tissue slices 63 a that are excised by means of theforceps 12 a and 12 b. Preferably, the depressions 72 a to 72 e have, adiameter of 4 to 10 mm and a depth (depth to the base portions) of about2 to 5 mm, for example.

Through slits 74 a to 74 e are formed in the centers between each ofdepressions 72 a to 72 e. These through slits 74 a to 74 e divide thetrap body 70 into a plurality of traps 75 a to 75 e that have thedepressions 72 a to 72 e, respectively.

A taper portion 76 is formed on the distal end of the trap body 70 so asto extend in the longitudinal direction of the trap body 70. A fingerknob 77 is formed on the proximal end of the trap body 70. Correspondingto the traps 75 a to 75 e, respectively, recesses 78 a to 78 e areformed in side faces (or at least one side face) of the trap body 70perpendicular to its upper surface in which the depressions 72 a to 72 eare formed. In the present embodiment, the recesses 78 a to 78 e areformed in both side faces of the trap body 70, paired corresponding toeach of the traps 75 a to 75 e. Each pair of recesses 78 a, 78 a (or 78b, 78 b; . . . ; 78 e, 78 e) corresponding to each of the traps 75 a to75 e are arranged symmetrically with respect to a central axis O3 ofeach of the depressions 72 a to 72 e and extend along the central axisO3 of the depressions 72 a to 72 e. A plane that passes through eachpair of recesses 78 a, 78 a (or 78 b, 78 b; . . . ; 78 e, 78 e)corresponding to each of the traps 75 a to 75 e passes substantiallythrough the central axis O3 of each corresponding depression 72 a (or 72b, 72 c, 72 d or 72 e) and extends substantially at right angles to thelongitudinal direction of the trap body 70.

Corresponding to the respective positions of the traps 75 a to 75 e,markings 84 a to 84 e are printed in Arabic FIGS. 1 to 5 on the uppersurface of the trap body 70. In the present embodiment, the Arabic FIGS.1 to 5 are emphasized by coating with a paint that inflicts no bodilyinjury on persons in medical facilities.

The through hole 46 for trap insertion of the tissue trap mountingportion 37 that is fitted with the tissue recovery trap 69 is designedso that the space between the front-side opening seal 43 and therear-side opening seal 44 that constitute the through hole, is a littleshorter than the width of the side faces of the trap body 70 (surfacesin which the recesses 78 a to 78 e are formed). As shown in FIG. 10A,moreover, the through hole 46 for trap insertion is formed havingretractable protrusions 79 a and 79 b individually on a pair of oppositesurfaces that are perpendicular to the front-side opening seal 43 andthe rear-side opening seal 44. These protrusions 79 a and 79 b areformed as a part of a plate spring 80 that is molded by bending astainless steel sheet, for example. Further, the protrusions 79 a and 79b are formed on a plane that connects the inner tube 8 and the suctionline 55. They have a size such that they can engage the recesses 78 a to78 e in the trap body 70 when they are projecting.

The support 71 is composed of an arm portion 81, an outer fittingportion 82, and a shoulder portion 83 having a U-shaped (groove-shaped)cross section. The arm portion 81 can engage the trap mounting portion37. The trap body 70 can be inserted into the outer fitting portion 82in its longitudinal direction. The shoulder 83 extends from the outerfitting portion 82 in the direction opposite to the extending directionof the arm portion 81 has a U-shaped cross section (groove shape), andguides and supports the trap body 70. The shoulder 83 has a groove widthsubstantially equal to the width of the side faces of the trap body 70in which the recesses 78 a to 78 e are formed (or the thickness of thetrap body 70) and a length substantially equal to the longitudinaldimension of the trap body 70.

The following is a description of the operation of the medicalinstrument 1 constructed in this manner.

First, the ring valve body 47 is connected to the supporting rod 32 ofthe instrument control section 3 before treatment. This is achieved byonly inserting the lure male 48 into the suction port 38 so that theouter surface of the lure male 48 mates with a lure-tapered surface ofthe inner surface of the suction port 38 and causing the internal threadon the inner surface of the rock ring 49 to screw-engage the projection50 on the outer surface of the suction port 38.

Subsequently, the external port 51 is connected to the negative-pressuregenerator 35 (see FIG. 1) by means of the suction tube 36, and thereturn port 56 is connected to the suction input connector (not shown)of the endoscope by means of the return tube 61. When the suctioncontrol slider 42 is not pulled to the proximal end at this time, thevalve spring 60 urges the push rod 52 to project from the slidingtubular line 53. Therefore, the valve seat 57 is situated between theinternal communication passage 58 and the external communication passage59. A negative pressure generated by the negative-pressure generator 35acts on the endoscope through the external communication passage 59,sliding tubular line 53, release tubular line 54, return port 56, andreturn tube 61. In this state, therefore, sucking operation can benormally carried out by means of the endoscope.

Before starting treatment, moreover, the trap body 70 and the support 71are combined so that the arm portion 81 of the support 71 is hooked overand fitted on the trap mounting portion 37, as shown in FIG. 8A. Asshown in FIG. 8B, thereafter, the trap body 70 is pushed in thelongitudinal direction (direction of the arrow in the drawing). Sincethe taper portion 76 is formed on the distal end of the trap body 70,the trap body 70 is then smoothly inserted into the through hole 46 fortrap insertion that is formed between the front-side opening seal 43 andthe rear-side opening seal 44. In this process of insertion, moreover,the protrusions 79 a and 79 b of the through hole 46 for trap insertionabut individually against the side faces of the trap body 70. If thetrap body 70 in this state is further pushed in, the plate spring 80 isdeformed so that the protrusions 79 a and 79 b sink and the trap body 70is inserted deeper (see FIG. 10A). When the recesses 78 a on the extremedistal end side of the trap body 70 reach the respective positions ofthe protrusions 79 a and 79 b, the protrusions 79 a and 79 b areprojected to engage the recesses 78 a by means of the repulsive force ofthe plate spring 80 (see FIG. 10B). When the protrusions 79 a and 79 bare in engagement with the recesses 78 a, moreover, the respectivecenters of the depression 72 a and the mesh filter 73 a are aligned withthe respective centers of the proximal end opening of the inner tube 8,opening 43 a of the front-side opening seal 43, opening 44 a of therear-side opening seal 44, and distal end opening of the suction line55, based on the aforesaid positional relation between the depression 72a and the recesses 78 a. Further, the space between the front-sideopening seal 43 and the rear-side opening seal 44 is a little shorterthan the thickness of the trap body 70 (width of the side faces). Whenthe trap body 70 is inserted so that the protrusions 79 a and 79 b arein engagement with the recesses 78 a, therefore, the inner tube 8,front-side opening seal 43, rear-side opening seal 44, and suction line55 are connected airtightly, so that an external inflow of air is cutoff.

Treatment is started when these preparations are completed. In thistreatment, the interior of the body cavity is observed through theendoscope as the endoscope and the medical instrument 1 are moved in thebody cavity, and the tissue picking portion 5 is guided to a positionwhere it faces the subject tissue 62 (see FIGS. 12 and 13) of a mucousmembrane. Subsequently, the forceps control slider 34 is moved to thedistal end side to push out the pair of forceps control wires 9 a and 9b to the distal end side. Thereupon, the distal end side of the forcepscontrol wires 9 a and 9 b is pushed out to the outside of the distal endof the insert section 2 through the forceps control wire outlet portions18 a and 18 b. Accordingly, the forceps control wire holding pins 23 aand 23 b that are fixed integrally to the forceps control wires 9 a and9 b rock as the rocking arms 21 a and 21 b that support them are pushedout toward the distal end side of the insert section 2. Since theforceps control wires 9 a and 9 b are provided with the bent portions 64a and 64 b in this case, the movable jaws 20 a and 20 b of the forceps12 a and 12 b rock independently around the forceps supporting pins 22 aand 22 b. Thus, the forceps 12 a and 12 b open on either side of thecentral axis of the tissue picking portion 5.

Subsequently, the sheath 4 is pushed into the forceps channel (notshown) of the endoscope with the movable jaws 20 a and 20 b open, andthe respective edge portions 25 a and 25 b of the movable jaws 20 a and20 b are caused to engage the subject tissue 62, as shown in FIG. 12. Inthis state, the forceps control slider 34 is moved to the proximal endside so that the pair of forceps control wires 9 a and 9 b are pulledback to the proximal end side. Thereupon, the forceps control wires 9 aand 9 b are pulled back to the proximal end side, so that the movablejaws 20 a and 20 b independently rock around the forceps supporting pins22 a and 22 b in the direction opposite to the direction of theaforesaid opening operation. Thus, a forceps opening that is defined bythe jaws is close. By this operation, the organic tissue 62 is excised,and the excised tissue slice 63 a is held in the tissue receiving space27 of the movable jaws 20 a and 20 b (see FIG. 13).

When the movable jaws 20 a and 20 b are fully closed in this manner, thebent portions 64 a and 64 b of the forceps control wires 9 a and 9 b areelastically deformed and stretched in a manner such that they touch andinterfere with the forceps control wire outlet portions 18 a and 18 b(see FIG. 13). If the forceps control slider 34 is unhanded so that aforce having so far been applied to the forceps control slider 34 (forceto pull back the forceps control wires 9 a and 9 b to the proximal endside) is removed in this state, therefore, the bent portions 64 a and 64b of the elastically deformed forceps control wires 9 a and 9 b areurged to restore their original bent molded shape by the restoring forceof the wires. As this is done, the forceps control wires 9 a and 9 bslightly move to the distal end side to reach a position where the bentportions 64 a and 64 b never touch or interfere with the forceps controlwire outlet portions 18 a and 18 b. Thereupon, the respective distalends of the movable jaws 20 a and 20 b naturally open to an angle widerthan about 10° and narrower than 45° (see FIG. 14). In consequence, apart of the tissue slice 63 a, excised and recovered, can be releasedfrom hold between the edge portions 25 a and 25 b of the movable jaws 20a and 20 b, if any.

Subsequently, the suction control slider 42 is grasped and pulled to theproximal end side. Thereupon, both the push rod 52 and the valve spring60 are pushed in toward the release tubular line 54 to close the openingon the side of the release tubular line 54, as shown in FIG. 7D,whereupon the sliding tubular line 53 and the release tubular line 54are disconnected. Accordingly, the negative pressure that acts on theexternal communication passage 59 is applied to the suction port 38through the sliding tubular line 53 and the internal communicationpassage 58. If the suction control slider 42 is released from a tractiveeffort, the valve spring 60 is restored to its original shape andstretched, whereupon the push rod 52 and the valve seat 57 return totheir original positions. Thus, the negative pressure from the returntube 61 is applied to the endoscope through the sliding tubular line 53,release tubular line 54, and return port 56, whereupon the negativepressure on the suction port 38 is removed.

If a fluid for reflux is forced out of the syringe 39 into the liquidconveying port 40 after the syringe 39 filled with the fluid is attachedto the liquid conveying port 40, the fluid flows from the liquidconveying port 40 into the residual space 28 in the sheath 4 through theliquid conveying line 41 and reaches the tissue receiving space 27 ofthe movable jaws 20 a and 20 b. Since the inner tube 8 and the suctionnozzle 13 are negatively pressurized through the suction port 38 onwhich the negative pressure acts, on the other hand, the tissue slice 63a that is held in the tissue receiving space 27 of the movable jaws 20 aand 20 b is sucked through the suction nozzle 13 into the inner tube 8and swept away by the fluid without jamming the inner tube 8. Finally,the tissue slice 63 a is sucked through the suction port 38 into themesh filter 73 a of the trap body 70 of the tissue recovery trap 69 andcaptured. More specifically, the tissue slice 63 a, sucked together withthe fluid into the inner tube 8, enters the depression 72 a and isstopped by the surface of the mesh filter 73 a. On the other hand, thefluid passes through the fine orifices of the mesh filter 73 a, and issucked from the suction tube 36 into the negative-pressure generator 35through the suction line 55, suction port 38, internal communicationpassage 58, sliding tubular line 53, and external communication passage59. Further, whether or not the tissue slice 63 a is in the depression72 a is visually confirmed through the tissue recognition window 45 ofthe transparent material behind the rear-side opening seal 44.

If the tissue slice 63 a is recognized through the tissue recognitionwindow 45, the finger knob 77 is pressed further to push the trap body70. As this is done, a bending force acts on the trap body 70. Since itsdeformation is prevented by the shoulder 83 of the support 71, however,the trap body 70 is restrained from being deformed or broken.

If the trap body 70 is thus pushed in, the plate spring 80 deformsoutward, whereupon the protrusions 79 a and 79 b sink and get out of therecesses 78 a. Further, the trap body 70 that holds the tissue slice 63a therein projects from the lower surface of the tissue trap mountingportion 37. It is fixed when the next recesses 78 b engage theprotrusions 79 a and 79 b. As this is done, the respective centers ofthe next depression 72 b and the mesh filter 73 b are aligned with therespective centers of the inner tube 8, front-side opening seal 43,rear-side opening seal 44, and suction line 55. Thereupon, preparationsfor the recovery of another tissue slice are completed. In this state,as shown in FIG. 11A, the trap body 70 projects from the lower surfaceof the tissue trap mounting portion 37 so that its through slits 74 aare exposed. If the trap 75 a is grasped and bent longitudinally,therefore, the trap 75 a can be easily severed from the trap body 70 atthe through slits 74 a. Thereafter, the trap 75 a, holding the tissueslice 63 a and severed, is put directly into a sample bottle 59 thatcontains a tissue fixing agent 61 therein, so that the tissue slice 63 ais immersed in the tissue fixing agent 61, as shown in FIG. 11C.

Tissue slices 63 b to 63 e are also recovered in due order in likemanner by the aforesaid operation with use of the other traps 75 b to 75e that remain in the trap body 70. After the last trap 75 e is severed,the finger knob 77 is held and pulled up, whereupon the trap body 70 andthe support 71 are removed entire from the tissue trap mounting portion37. Even after the traps 75 a to 75 e are severed, the tissue slices 63a to 63 e that are held individually in the traps can be easilydiscriminated, since the markings 84 a to 84 e are put on the individualtraps.

If more tissue slices are required, another combination of the trap body70 and the support 71 is prepared and attached to the tissue trapmounting portion 37, and the aforesaid operation is repeated. In thismanner, continuous operation for picking the subject tissue of themucous membrane in the body cavity by means of the medical instrument 1terminates.

In the medical instrument 1 of the present embodiment, as describedabove, the forceps control wire holding pins 23 a and 23 b are situatedon or near the reference plane P that passes through the longitudinalcentral axis O1 and extends parallel to the second rocking axis O2.Accordingly, one end portions (outward end faces) 98 of the forcepscontrol wire holding pins 23 a and 23 b on the side that face (or isopposed to) the tip cover flat portions 15 a and 15 b can be formedflat, so that a wide connection space (working space) for the forcepscontrol wires 9 a and 9 b can be secured. Thus, fixing the forcepscontrol wire holding pins 23 a and 23 b and the control wires 9 a and 9b by laser welding, spreading, etc. has no directivity, so that theworkability is improved. Since the pins are arranged in a region thathas a maximum outer diameter, moreover, projections from thecircumference of a circle can be lessened, so that the maximum outerdiameter of the tissue picking portion 5 can be reduced. Thus, theresistance of insertion of the endoscope into the forceps channellowers, so that the operating efficiency is improved.

In the configuration described in the aforementioned Jpn. Pat. Appln.KOKAI Publication No. 2000-279418, on the other hand, the forcepscontrol wires 209 a and 209 b are fixed by spreading, laser welding,etc. after they are passed through the forceps control wire holdinggrooves 224 a and 224 b formed in the forceps control wire holding pins223 a and 223 b. Since the forceps control wire holding pins 223 a and223 b are spaced individually outward from the central axis plane of theforceps (or the plane of contact between the edge portions 225 a and 225b of the movable jaws) (that is, the forceps control wire holding pins223 a and 223 b are located at a good distance from a plane that passesthrough the longitudinal central axis of the tissue picking portion 205(tip cover 211) and extends parallel to the longitudinal central axis ofthe forceps control wire holding pins 223 a and 223 b), the outward endfaces 223 f of the forceps control wire holding pins 223 a and 223 b areobliquely formed to match the circumferential surface C of the forceps(see FIG. 18C). This is done because the outer diameter of the medicalinstrument must be made smaller than the inner diameter of the forcepschannel of the endoscope, since the instrument is inserted in theforceps channel when it is used. In fixing the forceps control wires 209a and 209 b to the forceps control wire holding grooves 224 a and 224 bin the forceps control wire holding pins 223 a and 223 b by spreading orlaser welding, however, a satisfactory connection space (working space)for the forceps control wires 209 a and 209 b cannot be secured with useof an inclined working plane. Thus, positioning and fixing operationsare harder than when a substantially horizontal plane is used.Naturally, in order to give priority to workability, the respectiveoutward end faces 223 f of the forceps control wire holding pins 223 aand 223 b may possibly be formed to be substantially horizontal surfacesin the state of FIG. 18C where the forceps control wire holding pins 223a and 223 b are spaced outward from the central axis plane of theforceps. In this case, however, the corner portions of the substantiallyhorizontal surfaces project from the circumferential surface, so thatthe maximum outer diameter increases. Thus, the resistance of insertioninto the endoscope is so high that the operating efficiency lowers.

In the medical instrument 1 of the present embodiment, moreover, theforceps supporting pins 22 a and 22 b that have the first rocking axisO1 are formed integrally with the flat portions 15 a and 15 b. As isalso evident from FIG. 4B, therefore, the forceps supporting pins 22 aand 22 b never project into the bore of the tip cover 11. Thus, the sizeof the suction nozzle 13 that is passed through the bore of the tipcover 11 cannot be restricted.

Further, the medical instrument 1 of the present embodiment is formedhaving a plurality of bent portions 64 a and 64 b as springy moldedparts near the respective distal ends of the forceps control wires 9 aand 9 b, that is, in sections from the forceps control wire holding pins23 a and 23 b to the forceps control wire outlet portions 18 a and 18 b.The bent portions 64 a and 64 b are formed having a shape such that theynever interfere with the forceps control wire outlet portions 18 a and18 b when the respective distal ends of the movable jaws 20 a and 20 bare inclined at an angle less than 45° and not less than 10°. If themovable jaws 20 a and 20 b are fully closed, on the other hand, the bentportions 64 a and 64 b are brought into contact with the forceps controlwire outlet portions 18 a and 18 b, whereby the bent portions 64 a and64 b are elastically deformed. Thus, if the operator releases his/herhold of the forceps control slider 34 so that no operating force acts onit, the respective distal ends of the movable jaws 20 a and 20 bautomatically open at an angle less than 45° and not less than 10°. If anegative pressure is applied to the suction nozzle 13 in this state, thetissue slice 63 a is pulled into the suction nozzle 13 without beingnipped between the edge portions 25 a and 25 b. Thus, the tissue slices63 a, . . . can be securely sucked in and recovered without any specialoperation by the operator.

In the medical instrument 1 of the present embodiment, moreover, thesuction port 19 at the distal end of the suction nozzle 13 has an outerdiameter such that it can be held in the tissue receiving space 27 ofthe movable jaws 20 a and 20 b. Further, the proximal end side portion85 of the suction nozzle 13 has an oval cross section of an area wideenough to allow the passage of the tissue slice 63 a. Furthermore, thetaper portion 86 is formed on the transit section from the suction port19 to the proximal end side portion 85. The taper portion 86 has asmooth surface that connects the suction port 19 having a circular crosssection and the inner surface of the proximal end side portion 85. Thus,the tissue slices 63 a, . . . that are held in the tissue receivingspace 27 of the jaws 20 a and 20 b can smoothly deform and pass throughthe suction port 19, taper portion 86, and proximal end side portion 85without jamming. If the tissue slices 63 a, . . . have sizes that matchthe capacity of the tissue receiving space 27, therefore, they can besecurely recovered without damage.

In the configuration described in the aforementioned Jpn. Pat. Appln.KOKAI Publication No. 2000-279418, on the other hand, the suction port219 at the distal end of the suction nozzle 213 has an oval shape thatmatches the opening portion 216 of the tip cover 211, which is smallerthan the cross section of the tissue receiving space 227 of the movablejaws 220 a and 220 b. If the tissue receiving space 227 of the movablejaws 220 a and 220 b is filled with the picked tissue slice 263,therefore, pulling the tissue slice 263 into the suction port 219requires deformation under suction pressure. Thus, the edge of thesuction port 219 may possibly damage the tissue slice 263. If the tissueslice is hard, it cannot be deformed and may possibly remain in thetissue receiving space 227 of the movable jaws 220 a and 220 b withoutbeing recovered.

In the present embodiment arranged in this manner, however, the tissueslices 63 a, . . . that are excised by means of the forceps aregradually deformed as they are attracted to the suction port 19 bysuction and pass through the taper portion 86. Finally, the tissue sliceis deformed to a diameter such that it can get into the inner tube 8,and is sucked into the inner tube 8.

Further, the control section body 31 of the medical instrument 1 of thepresent embodiment is provided with the tissue trap mounting portion 37.The mounting portion 37 can receive the trap body 70, which has the meshfilters (filter elements) 73 a to 73 e and chambers that hold thetissues. The trap body 70 can be divided into the individual traps 75 ato 75 e. Thus, the tissue slices 63 a to 63 e can be held individually,and the mesh filters 73 a to 73 e can be changed on the course of theinner tube 8 by simple operation. Further, the tissue slices 63 a to 63e can be handled with ease, so that the operator's labor can be saved,and the working time can be shortened.

In the configuration described in the aforementioned Jpn. Pat. Appln.KOKAI Publication No. 2000-279418, on the other hand, a plurality ofvials 246 a to 246 f are attached to the housing of the tissue recoverycontainer 237. In recovering a plurality of tissues, however, meshfilters 252 a to 252 f must be caused to project over the suction line255 by suitably pushing in the vials 246 a to 246 f in the order basedon the vicinity to the distal end. Since these vials are located closeto one another, they may possibly be pushed wrongly or in a wrong order.If the vials 246 a to 246 f are pushed in a wrong order, it is hard tomatch the regions of patient's body from which a plurality of tissueslices are picked to records. Thus, accurate diagnosis may possibly behindered.

In the medical instrument 1 of the present embodiment, moreover, thetissue recognition window 45 is formed of a transparent material, sothat whether or not the tissue slices 63 a, . . . are captured by themesh filters 73 a to 73 e can be visually confirmed. Thus, whether ornot the tissue slices 63 a, . . . are recovered can be confirmed withoutmoving the trap body 70, so that the working time can be shortened bythe omission of a step of operation. In the present embodiment, thetissue receiving space 27 of the movable jaws 20 a and 20 b, the meshfilters 73 a to 73 e, and a part of the trap body 70 may be formed of atransparent material. In this case, whether or not the tissue slices 63a, . . . are captured can be visually confirmed from the outside, sothat whether or not the tissue slices 63 a, . . . are recovered can beconfirmed without moving the trap portion. Thus, the working time can beshortened by the omission of a step of operation.

In the medical instrument 1 of the present embodiment, furthermore, thesuction control slider 42 is supported by means of the supporting rod 32of the instrument control section and is slidable just behind theforceps control slider 34. Further, the valve spring 60 and the push rod52 engage the suction control slider 42, and application of the negativepressure from the return port 56 to the suction port 38 can be switchedby axially moving the valve seat 57 that is fixed to the push rod 52.Accordingly, unloading the force to pull the forceps control slider 34and switching the negative pressure application can be achievedsimultaneously and alternatively by simply releasing the hold of theforceps control slider (first movable slide member) 34 and pulling thesuction control slider (second movable slide member) 42 toward theproximal end side. Thus, the movable jaws 20 a and 20 b can beautomatically opened to ensure smooth suctional recovery operation onlywhile the negative pressure is acting on the suction port 38.

With the conventional medical instrument, the operator manipulates theforceps control slider 34 only. In general, therefore, the forcepscontrol slider 34 is often kept held while a tissue slice is being held.Therefore, release of the forceps control slider 234 requires someexperience and may possibly result in wrong operation as the tissueslice 263 leaves the nipped tissue and is drawn in to a position withinreach by suction. According to the present embodiment, however, thisproblem can be solved.

In the present embodiment, moreover, the liquid conveying port 40 islocated near the suction control slider 42 and in the vicinity of theproximal end of the supporting rod 32. While the fluid is beingdelivered with the syringe 39 mounted in position, therefore, theoperator holds the grip ring 33 and the suction control slider 42 with apull. Therefore, the region in which the operator holds the instrumentcontrol section 3 is situated close to the point of operation on thefluid delivery portion, so that the syringe 39 can be easily pushed inwith a greater force.

In the configuration described in the aforementioned Jpn. Pat. Appln.KOKAI Publication No. 2000-279418, on the other hand, the liquidconveying port 240 to which the syringe 239 for delivering the fluidinto the residual space 228 in the sheath 204 is attached is set in aposition nearer to the distal end of the control section body 231. Whenthe fluid is actually delivered, however, the position for the operationto push in the piston of the syringe 239 is distant from the position(of the grip ring 233 and the forceps control slider 234) in which themedical instrument is held, so that the manipulation is not easy. Ifthere is a distance between these two points, moreover, a bending forceacts on the control section 3, and furthermore, the holding operationmay possibly be laborious.

In the present embodiment, moreover, the ring valve body 47 has thereinthe inner tube 8 of the biopsy forceps and a valve function thatalternatively connects the suction connector (not shown) of theendoscope to the negative-pressure generator 35. For the valve function,there are provided the push rod 52, valve seat 57, sliding tubular line53, release tubular line 54, internal communication passage 58, externalcommunication passage 59, and valve spring 60. When the suction controlslider 42 is not operating, therefore, the push rod 52 and the valveseat 57 are urged in one direction by the restoring force of the valvespring 60. Thereupon, a negative pressure from the negative-pressuregenerator 35 is applied to the endoscope through the return tube 61 viathe sliding tubular line 53, release tubular line 54, and return port56. Thus, suction of the endoscope can be used normally. If the suctioncontrol slider 42 is pulled toward the proximal end side, on the otherhand, the push rod 52 and the valve seat 57 are actuated, whereupon thenegative pressure is applied to the interior of the inner tube 8 throughthe sliding tubular line 53 and the internal communication passage 58.Thus, the destination of the negative pressure from thenegative-pressure generator 35 can be switched to the endoscope or thebiopsy forceps by simple operation to switch the suction control slider42 on or off. In consequence, the steps of procedure of the operationcan be simplified, and an effect can be expected that there is nopossibility of wrong operation.

In the configuration described in the aforementioned Jpn. Pat. Appln.KOKAI Publication No. 2000-279418, on the other hand, the tissuerecovery container 237, suction tube 236, and suction means 235 areconnected directly to one another. Thus, a dedicated device for themedical instrument is indispensable as the suction means 235. Generalhospital facilities are provided with suction means to be connected toan endoscope for treatment. However, few of them can prepare dedicatedsuction means for the medical instrument. In using the medicalinstrument 1 with suction means for endoscope, therefore, many hospitalfacilities solve this problem by using a valve unit for suitablyswitching the endoscope over to the medical instrument. The medicalinstrument 1 requires the use of the suction means 35 for only a momentbefore the tissue slice 263 is recovered. Preferably, therefore, thesuction means 235 should be kept connected to the endoscope at any othertime. The present embodiment can solve or remove these problems andtroubles.

FIGS. 15A to 16D show a second embodiment of the present invention. Thepresent embodiment is a modification of the first embodiment. In thedescription to follow, therefore, like numerals are used to designatecomponents that are shared by the first embodiment, and a description ofthose components is omitted.

In the present embodiment, support holes 112 a and 112 b of forceps 12 aand 12 b have a diameter larger than that of forceps supporting pins 22a and 22 b that are formed integrally with flat portions 15 a and 15 bof a tip cover 11. On the other hand, stopper pins 115 a and 115 b havean inner diameter such that they can receive the forceps supporting pins22 a and 22 b and an outer diameter such that they can be inserted intothe support holes 112 a and 112 b. Their respective first ends areformed having collar portions (spread portions) 113 a and 113 b. Thus,in the present embodiment, the tubular pins 115 a and 115 b are arrangedso that they are fitted on the forceps supporting pins 22 a and 22 bthat define a first rocking axis O1. The pins 115 a and 115 b arecomposed of shank portions 114 a and 114 b and the spread portions 113 aand 113 b, respectively (see FIG. 15A). The shank portions 114 a and 114b have inner and outer diameters such that they can be fitted betweenthe respective inner surfaces of the support holes 112 a and 112 b ofthe forceps 12 a and 12 b and the forceps supporting pins 22 a and 22 bto support the forceps 12 a and 12 b, respectively. The spread portions113 a and 113 b are formed on the respective distal ends of the shankportions 114 a and 114 b that project from the support holes 112 a and112 b, respectively. Their outer diameter is larger than that of theshank portions 114 a and 114 b.

After the forceps supporting pins 22 a and 22 b are passed through thesupport holes 112 a and 112 b of the forceps 12 a and 12 b,respectively, in this configuration, the stopper pins 115 a and 115 bare inserted. The boundaries between the forceps supporting pins 22 aand 22 b and the collar portions 113 a and 113 b are welded and unifiedby laser welding or the like. Thereupon, the forceps 12 a and 12 b aresupported on the flat portions 15 a and 15 b of the tip cover 11,respectively, for rocking motion.

Besides the effect of the first embodiment, according to thisconfiguration, the collar portions 113 a and 113 b can be formed bywelding without mechanically spreading the forceps supporting pins 22 aand 22 b, so that the productivity can be improved, and the possibilityof material deformation that is attributable to mechanical spreading canbe eliminated.

In the configuration described in the aforementioned Jpn. Pat. Appln.KOKAI Publication No. 2000-279418, on the other hand, the forcepssupporting pins 222 a and 222 b are held penetrating the flat portions215 a and 215 b of the tip cover 211. After the forceps 212 a and 212 bare supported from outside, the respective distal ends of the forcepssupporting pins 222 a and 222 b are spread and fixed by laser welding orthe like, whereby the forceps 212 a and 212 b and the forceps supportingpins 222 a and 222 b are fixed integrally to one another. However, therespective head portions of the forceps supporting pins 222 a and 222 bproject into the bore of the tip cover 211. Owing to the presence ofthese head portions, the width of the suction nozzle 213 with an ovalcross section, which is also set in the bore of the tip cover, must belessened. This is unfavorable because the deformation increases as atissue slice is sucked into the bore of the suction nozzle 213. As theforceps 212 a and 212 b rotate, moreover, the outer peripheral surfaceof the suction nozzle 213 may touch the head portions of the forcepssupporting pins 222 a and 222 b. Owing to frictional resistance producedin these parts, therefore, the operation may possibly slow down.

It is to be understood that the present invention is not limited to theembodiments described above, and that various changes and modificationsmay be effected therein without departing from the scope or spirit ofthe invention. In the embodiments described above, for example, thecontrol wires 9 a and 9 b are connected directly to the forceps 12 a and12 b by means of the pins 23 a and 23 b. Alternatively, however, thecontrol wires 9 a and 9 b may be connected to the forceps 12 a and 12 bby means of a link mechanism or the like.

1. A medical instrument comprising: a tubular sheath; a tip coverpositioned on a distal end of the tubular sheath, the tip cover having aswingable operating section on a distal end portion of the tip cover,the swingable operating section formed of a pair of forceps, each ofwhich rocks individually around a respective first rocking axiscorresponding thereto; the tip cover further having a proximal endportion having a circular cross section perpendicular to a longitudinalcentral axis of the circular cross section and a pair of parallel flatportions symmetrically formed on an external surface of the distal endportion, the pair of parallel flat portions being in sliding contactwith respective proximal end portions of the forceps; a nozzle extendingfrom the tip cover and configured for receiving tissue cut by the pairof forceps; a pair of manipulators which advance and retreat along thelongitudinal central axis of the tubular sheath, thereby rocking theforceps around the first rocking axis; and a pair of junctions whichrespectively connect the manipulators for rocking motion around a secondrocking axis to the forceps in the flat portions, the junctions beingsituated substantially on a reference plane containing the longitudinalaxis of the tubular sheath and extending parallel to the second rockingaxis, when the operating section is closed; wherein the first rockingaxis of each forceps is not on the reference plane when the operatingsection is closed.
 2. A medical instrument according to claim 1, whereina plane passing through the first rocking axis and extending parallel tothe reference plane is not coincident with a plane passing through thesecond rocking axis and extending parallel to the reference plane.
 3. Amedical instrument according to claim 1, wherein the first rocking axisis not on the reference plane.
 4. A medical instrument according toclaim 1, wherein the manipulator and the junction have wires and pins,respectively.
 5. A medical instrument according to claim 1, whichfurther comprises a recovery line located on the proximal end side ofthe forceps and used to recover an organic tissue, control wires formingthe manipulator, passed through the sheath, and adapted to be connectedto the forceps by the junction after being led out of the sheath throughthe distal end portion, outlet portions at the distal end portionthrough which the control wires are led out of the sheath, and a slidemember connected to the respective proximal end portions of the controlwires and serving to move the control wires in the axial directionthereof, thereby opening or closing the forceps; and wherein the controlwire is provided with a springy molded part premolded into apredetermined shape, the molded part being adapted to be deformed fromthe predetermined shape and engage the corresponding outlet portion whenan operating force is applied to the slide member so that the forcepsare fully closed, and the molded part being adapted to be restored tothe predetermined shape so that the molded part and the outlet portionare disengaged and the forceps are urged to open when the slide memberis released from the operating force.
 6. A medical instrument accordingto claim 1, wherein the first rocking axis is composed of shank portionsprotruding radially outward from the flat portions and spread portionsformed on the respective distal ends of the shank portions correspondingthereto and larger in outer diameter larger than the shank portions. 7.A medical instrument according to claim 6, wherein the spread portionsare formed by spreading the shank portions.
 8. A medical instrumentaccording to claim 1, which further comprises tubular pins fitted on thefirst rocking axis, and wherein each of the forceps has a support holepenetrated by the first rocking axis, each of the pins being composed ofa shank portion, having inner and outer diameters such that the pin canbe fitted between the inner surface of the support hole of the forcepsand the first rocking axis to support the forceps, and a spread portionformed on the distal end of the shank portion projecting from thesupport hole and having an outer diameter larger than that of the shankportion.
 9. A medical instrument according to claim 8, wherein thespread portions are welded to the first rocking axis.
 10. A medicalinstrument according to claim 1, wherein the junctions are situated in aregion that has a maximum outer diameter of the circular cross sectionwhen the operating section is closed.
 11. A medical instrument accordingto claim 1, wherein the manipulators are made of one of a stainlessspring steel and a superelastic alloy.
 12. A medical instrumentaccording to claim 1, wherein the nozzle has a port formed at a distalend of the distal end portion to outwardly open, and a bore extendingalong the longitudinal central axis and communicated with the port. 13.A medical instrument according to claim 1, wherein the manipulatorsinclude a pair of wires, and the junctions include a pair of pins whichare respectively connected to the wires.
 14. A medical instrumentaccording to claim 1, wherein the pair of junctions disposed about thesecond rocking axis are formed so as not to project into a bore of thedistal end portion.
 15. A medical instrument according to claim 1,further comprising a pair of supporting pins disposed about the firstrocking axis and formed integrally with the parallel flat portions so asnot to project into a bore of the distal end portion.
 16. A medicalinstrument according to claim 1, wherein the pair of junctions arerotatably supported at the proximal end portions and are rotatably anddirectly fixed to the pair of manipulators.
 17. A medical instrumentaccording to claim 1, wherein the junctions do not situate on thereference plane, when the operation section is opened.